ABSTRACT Support is requested for a Keystone Symposia conference entitled Mitochondria in Aging and Age-Related Disease, organized by Drs. Gerald S. Shadel and Holly Van Remmen. The conference will be held in Keystone, Colorado from January 13-17, 2019. Aging is the largest risk factor for most human diseases, yet the underlying reasons for this are not clear and hence remain under intense investigation. Mitochondria have long been associated with aging as the cornerstones of the ?mitochondrial? and ?free radical? theories of aging. However, that the role of mitochondria in aging is simply due to declines in ATP production and increased oxidative stress via reactive oxygen species production is giving way to more complex hypotheses. These are driven by the realization that mitochondria are dynamic and have multiple additional roles in cell and organismal physiology (e.g., signaling and immunity). The goal of this meeting is to bring together investigators working at the interface of mitochondria and aging to begin to develop network theories of mitochondrial contributions to aging and age-related diseases that take into account both ?old? and ?new? functions of mitochondria. Topics covered will include neurodegeneration, cancer, metabolic diseases, inflammation and mitochondrial signaling pathways. This meeting is being held jointly with that on Mitochondrial Biology in Heart and Skeletal Muscle, allowing in-depth coverage of mitochondria in cardiovascular aging and sarcopenia. It is expected that this meeting will facilitate new interactions and collaborations at the interface of aging and mitochondrial biology. This should catalyze new research toward therapies for age-related diseases based on selectively targeting mitochondrial functions and signaling pathways in specific physiological and disease contexts. Workshops will highlight work from exciting new investigators.